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We are offering hosted VoIP. The Asterisk servers are running in our data center and customers connect their Aastra phones remotely to it. However, I have one customers connected to his own PBX and he is having connection issues. The phones often lose their connection to the server (No service) and sometimes their ongoing call is simply cut off and all phones lose connection to the server. I have checked the logs but there doesn't seem to be anything unusual, so I have started to wonder if their hardware setup might be the cause.

Here is how they are setup :

Their Internet connection arrives at their office from a modem, which is then connected to their ISP router to provide their static IP. This then goes in their Netgear router for a DHCP server. Then, this is connected to their 3com Switch to provide all their office.

Their phones are connected to the switch and their computer are connected to their phones. I was wondering if the setup, or the switch/router could be the problem. I have ordered a new switch and a new router, as the switch is pretty old.

I would like to know if you guys have any idea that could help me find the source of this problem. I can provide more information if needed.

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Check if the Aastra phones have any NAT keepalive functions turned on. If they don't, turn it on. – Haakon Feb 13 '10 at 14:51
up vote 0 down vote accepted

They're sending their voice calls through a netgear router over the Internet to your data center? If the router isn't made for business class data transfers (i.e., is it a SOHO router for home users?) then I wouldn't be surprised if it's being overwhelmed and going glitchy. I didn't see in your mention of the configuration how many systems are on their network going through this router or stats on things like jitter or quality of service for their call dropping issues. Without stats on how much data you're pumping through the router (or even what kind of netgear router it is) it would be hard to definitively tell, but again, not surprised if it's a little SOHO router if that's what's causing the drops.

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There is only 3 phones in use at their place, but they are indeed using a simple Netgear router :…. So they have 3 phones and 3 computer connected to this router. – Philippe Feb 8 '10 at 14:15
What speed is their connection to the Internet? I have a simple SOHO router type setup at home with DSL (1 meg up, ~300 or 400k down) and two systems watching youtube content can make anything else on the network stutter to a standstill. Worse if you use Hulu; one system can barely watch anything, and someone browsing non-static content will risk making a Hulu vid stutter. A couple bi-directional voice calls could conceivably cause issues even with six network devices coupled with a low-end router. – Bart Silverstrim Feb 8 '10 at 14:20
I suspected that the router was at cause. Do you know if there are routers that don't require ample configuration, can be used as DHCP and optimized for VoIP that I could recommend to this customer? @Bart : They have a High speed Internet conenction 10mb down 1 mb up – Philippe Feb 8 '10 at 14:21
I would think that the speed is adequate (without numbers it's speculation). Router-offhand, if they got a low-end Cisco router they should be fine, since once it's configured it should chug along without alteration again for a very long time (don't know about you, but for me SOHO routers tend to die after a year or two anyway, but are commodity in that they cost $50 to $70 to replace). They could use a cheap PC with two cards and Linux, and you could get a lot of monitoring and remote access options with that in place. Perhaps others can recommend specific router appliances by name? – Bart Silverstrim Feb 8 '10 at 15:06
Or a turnkey bootable router distro based on Linux/BSD is also possible using inexpensive hardware too. Plenty of those available that work fairly well. Just google "linux router" with bootable or iso in the keywords should do it. – Bart Silverstrim Feb 8 '10 at 15:07

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